Usage

Arguments

The aesthetic mapping, usually constructed with
aes or aes_string. Only needs to be set
at the layer level if you are overriding the plot defaults.

data

A layer specific dataset - only needed if you want to override
the plot defaults.

stat

The statistical transformation to use on the data for this
layer.

position

The position adjustment to use for overlapping points
on this layer

show_guide

should a legend be drawn? (defaults to FALSE)

...

other arguments passed on to layer. This can
include aesthetics whose values you want to set, not map. See
layer for more details.

Details

With its siblings geom_hline and geom_vline, it's useful for
annotating plots. You can supply the parameters for geom_abline,
intercept and slope, in two ways: either explicitly as fixed values, or
in a data frame. If you specify the fixed values
(geom_abline(intercept=0, slope=1)) then the line will be the same
in all panels. If the intercept and slope are stored in the data, then
they can vary from panel to panel. See the examples for more ideas.